Regarding the Nessus Sphinx reported by Stephenie Armstrong, they are likely fairly common here in Peterborough County, though I rarely see them myself. They do, however, seem to be a day-flier, and can therefore be confused with a Hemaris species like the Snowberry Clearwing.
A few weeks ago, at my friend’s place near Warsaw, we were getting up to two dozen Gallium Sphinx
(Bedstraw Hawkmoths) at a time at her sprawling honeysuckle bush at dusk. More to follow soon about them. I got some excellent pictures!
I’ve seen 41 Monarchs now, and the first was the earliest ever for me – May 30th!
(Only one Giant Swallowtail, however, and it was on the same date as the first Monarch).